The use of microfluidic technology has been proposed for use in a number of analytical chemical and biochemical operations. These technologies provide advantages of being able to perform chemical and biochemical reactions, macromolecular separations, and the like, that range from the simple to the relatively complex, in easily automatable, high-throughput, low-volume systems. In particular, these systems employ networks of integrated microscale channels in which materials are transported, mixed, separated and detected. The small size of these systems allows for the performance reactions at substantially greater rates, and with substantially less reagent volume. Further, the development of sophisticated material transport systems has permitted the development of systems that are readily automatable and highly reproducible.
Because of their small size, microfluidic systems have typically required the use of relatively sophisticated detection systems to monitor the progress and results of the operation being performed by the system. In particular, as noted above, the extreme small scale of some microfluidic systems results in very small volumes of reagents, samples and the like, being used. Consequently, the amount of material that can be ultimately detected, e.g., using an optical detection system, is also very small. In order to address these issues, detection systems have become more sophisticated to either boost the detectable signal produced from material sought to be detected, increase the sensitivity of the instrumentation, or a combination of the two. For example, microscopes equipped with photomultipliers enhance the ability to detect fluorescently labeled materials within microscale channels. Further, the use of laser-induced fluorescence also enhances the amount of signal produced from these fluorescent materials.
Although these sophisticated detection systems have addressed many of the problems associated with detection in microscale fluidic channels, a number of problems remain, such as difficulty in optimally aligning these instruments, the cost and sophistication of providing robust optics for such systems and the like. Further, as the number of applications for microfluidic systems increases, it will include a similar increase in the type of optical detection systems to be used. The use of specifically tailored detection systems for each different application will present a likely prohibitive cost barrier. The present invention addresses many of the problems outlined above, as well as others.